Howlett doubled the club membership in 2008 when the All Blacks wing helped Munster to their second Heineken Cup title. Howlett was already a Super 14 winner with Auckland Blues in 2003.
One of that quartet hopeful of joining Kafer and Howlett is Wannenburg, capped 20 times by South Africa and a Super 14 winner with the Blue Bulls in 2007, 2009 and 2010, who has helped Ulster Rugby into the Heineken Cup quarter-finals where they will meet Northampton Saints on Sunday, 10 April.
"Winning the Super 14 the first time was quite fantastic - to be the first South African side to win the title was a real honour," said Wannenburg, whose 2007 Super 14 success against the Sharks came against a trio of players who are now his Ulster team-mates - prop BJ Botha, lock Johann Muller and scrum half Ruan Pienaar - in the first all South African final.
"It was a very tough game that could easily have gone either way and, while it was tough for the Sharks players, we were delighted to win it at the death."
Pedrie is only recently back in Belfast after a visit to his native South Africa from where he returned with some news for his team-mates.
"Evette and I got married near Johannesburg with around 220 guests joining us at the ceremony but now we are back and I am really enjoying my rugby and time with Ulster," he said.
"We have a great squad with a nice blend of youth and experience and we have so much to look forward to with the Heineken Cup quarter-finals coming up.
"I always wanted to play in the Heineken Cup - the group stages were super - but now we are through to the quarter-finals with everything to play for.
"The Heineken Cup is a really interesting and hard competition and it was really good playing against French, English and Italian teams.
"The Heineken Cup and the Super 15 are very close in physicality, the Heineken Cup is certainly right up there in that respect, but I guess they are also two different sorts of games.
"Because the Heineken Cup is played in the winter it is probably a bit slower whereas with the Super 15 being played in the summer it is a bit quicker. "Our home match against Biarritz Olympique is a good example. It was a hell of a game that went right down to the wire and, although the conditions were not great, it was fantastic to pull off the late win and get through to the quarter-finals.
"Everyone would prefer to have a home quarter-final but we will take a quarter-final anywhere.
"Once you are through to the knock-out stages anything can happen - it is sudden death and you have to be prepared for the challenge and then be ready to be physical.
"I have seen a couple of Northampton's games and they are obviously a very good side. It is going to be hard and fast and our kicking will have to be up to standard - it is going to be very tough match."
But back to that rare north-south double and Wannenburg is joined in that bid by those three other players. Those also with one southern title down and one northern title to go are Leicester Tigers' back Hamilton and fellow All Black and Biarritz Olympique prop Johnstone (both Crusaders 2005 and 2006) and Toulon flanker Smith, the 110-times capped Wallaby star a winner with the ACT Brumbies in 2001 and 2004.